Those are indeed 10:1 4AGE pistons (9.4:1 engines are actually 4AGEC engines - "C" stands for catalyst equipped ) These pistons were in some areas in Europe, and in Singapore, where no cats were required. 4AGEC TVIS 9.4:1engines make 112-115hp, smallport makes 130hp, the Singapore, and some areas of Europe TVIS 10:1 piston versions are alleged to make 125hp